InterSystems ObjectScript is a scripting language to operate with data using any data model of InterSystems Data Platform (Objects, Relational, Key-Value, Document, Globals) and to develop business logic for serverside applications on InterSystems Data Platform.
Caché offers a number of methods for going through a collection and doing something with its elements. The easiest method uses a while-loop and lets you fulfill the task in an imperative manner. The developer needs to take care of the iterator, jumping to the next element and checking if the loop is within the collection.
Embedded SQL is a tool that allows us to execute SQL statements in Caché Object Script. For example, to select the name of a person with a particular SSN from the Sample.Person class we can do the following:
I was recently asked whether we have a function to convert LDAP date time stamps into $HOROLOG format or other formats and the answer is not at the moment, but there is a simple method to do the conversion.
Let us look at the facts and figures involved...
1) Active Directory's (AD) date 0 (zero) is 1601-01-01 00:00:00.000 or January 1st, 1601 at midnight (00:00:00)
2) AD timestamps are calculated as the number of 100 nanosecond intervals from date 0
3) 864000000000 is the number of 100 nanosecond intervals per day
This article will describe and include an example of how to embed an external PDF file into an HL7 segment, specifically ADT_A01:2.3.1 OBX(). This can be useful when attempting to insert pictures or other external data into an HL7 message. In this example, the name of the PDF file to be embedded is provided in the incoming HL7 message in OBX(1):ObservationValue field.
In this article I would like to tell you about macros in InterSystems Caché. A macro is a symbolic name that is replaced with a set of instructions during compilation. A macro can “unfold” in various instruction sets each time it is called, depending on the parameters passed to it and activated scenarios. This can be both static code and the result of ObjectScript execution. Let's take a look at how you can use them in your application.
Here you have an easy way to write and execute COS code from your unix scripts. This way one does not need to write routines or even open Studio or Atelier. It can be an option for simple and small actions for instance things like installation tasks or compiling.
See sample bash script (compile.sh) to compile classes:
With a routine like this one, you can quickly calculate how many lines of code you are working with. And it is not only for routines, it works for classes because remember that classes generate routines !
Now, let’s say you can’t access the terminal or simply you just rather execute it from a web interface. In this article, I will show you how to execute terminal commands from a simple web page.
For example, in the image below you see how we execute $zv on a webpage:
Have some free text fields in your application that you wish you could search efficiently? Tried using some methods before but found out that they just cannot match the performance needs of your customers? Do I have one weird trick that will solve all your problems? Don’t you already know!? All I do is bring great solutions to your performance pitfalls!
As usual, if you want the TL;DR (too long; didn’t read) version, skip to the end. Just know you are hurting my feelings.
Process-private Globals can be used as a data global in storage definition. That way, each process can have its own objects for the class with ppg storage. For example lets define a pool, which can:
Just like Caché pattern matching, Regular Expressions can be used in Caché to identify patterns in text data – only with a much higher expressive power. This article provides a brief introduction into Regular Expressions and what you can do with it in Caché. The information provided herein is based on various sources, most notably the book “Mastering Regular Expressions” by Jeffrey Friedl and of course the Caché online documentation. The article is not intended to discuss all the possibilities and details of regular expressions. Please refer to the information sources listed in chapter 5 if you would like to learn more. If you prefer to read off-line you can also download the PDF version of this article.
Several years ago, long before Developer Community Portal was launched, I published a series of Caché tricks at one of Czech web sites. In this article, I’m posting translated version of one of them.
Capturing output of someone else’s methods or routines
Suppose you, or someone else created a useful method or routine, that was producing some computation that you’d like to benefit from, but the routine was writing output to process principal device.
You would like to use the data, but you need it not written to a device, but assigned to a variable. And, for any reason, you can’t modify the code. What can you do?
While Studio and Atelier are useful development interfaces, there are occasionally situations where a quick edit needs to be made to code and only terminal access is available. A useful set of tools to do this are the zload, zprint, zinsert, zremove, and zsave commands. These are abbreviated to zl, zp, zi, zr, and zs respectively. While each of these commands has its own page in documentation, this article will synthesize that information with examples to provide instruction for their combined use.
Order is a necessity for everyone, but not everyone understands it in the same way
(Fausto Cercignani)
Disclaimer: This article uses Russian language and Cyrillic alphabet as examples, but is relevant for anyone who uses Caché in a non-English locale. Please note that this article refers mostly to NLS collations, which are different than SQL collations. SQL collations (such as SQLUPPER, SQLSTRING, EXACT which means no collation, TRUNCATE, etc.) are actual functions that are explicitly applied to some values, and whose results are sometimes explicitly stored in the global subscripts. When stored in subscripts, these values would naturally follow the NLS collation in effect (“SQL and NLS Collations”).
NewBie's Corner Session 2 Variables Set and Write commands
Welcome to NewBie's Corner, a weekly or biweekly post covering basic Caché Material.
Session 2 – Click on the Caché Cube in your system tray and select Terminal to try out the commands.
Variables
Like other computer programming languages, Caché uses Variables and the values they represent to control programming. Variables are elements that represent data values. Manipulating and interrogating variables is at the root of programming.
If you want to import data from a mySQL export file (exported with mysqldump), you will find here a little script that could help.
Only the INSERT commands in the sql file are executed into Caché. Indices are not computed for better performance. %NOINDEX, %NOCHECK and %NOLOCK are generated on each INSERT line.
Currently, the file can not contain a "),(" pattern inside the values part of the INSERT command. If this is the case, the line is skipped. This feature may be implemented in the extractValuesList method.
The topic of for/while loop performance in Caché ObjectScript came up in discussion recently, and I'd like to share some thoughts/best practices with the rest of the community. While this is a basic topic in itself, it's easy to overlook the performance implications of otherwise-reasonable approaches.
I believe the simplest is (to work with csv delimited by ";"):
set file = ##class(%File).%New( "data.csv" )
set sc = file.Open( "R" )
if $$$ISERR(sc) quit ; or do smth
while 'file.AtEnd {
set str=file.ReadLine()
for i=1:1:$length( str, ";" ) {
set id=$piece( str, ";" ,i )
write !, id // or do smth
}
}
do file.Close()
Possible options:
different variants of error handling with sc code.
This article is a small overview of a tool that helps to understand classes and their structure inside the InterSystems products: from IRIS to Caché, Ensemble, HealthShare.
In short, it visualizes a class or an entire package, shows the relations between classes and provides all the possible information to developers and team leads without making them go to Studio and examine the code there.
If you are learning InterSystems products, reviewing projects a lot or just interested in something new in InterSystems Technology solutions — you are more than welcome to read the overview of ObjectScript Class Explorer!
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